Photoelectric sensor

Abstract

Light emitted from light-projecting elements constituted by LEDs (light-emitting diodes) or the like is transmitted to a light-projecting optical system of a sensor head portion through an optical fiber cable and projected from the light-projecting optical system onto an object. The light projected onto the object is reflected on the object. The reflected light is made incident on a light-receiving optical system. The light incident on the light-receiving optical system is led to a light-receiving element. The light-receiving element detects the incident light and generates a light-receiving signal based on the quantity of the detected light. The light-receiving signal generated by the light-receiving element is transmitted to a signal processing control portion of a main body portion through a light-receiving circuit and an electric wire cable.

1. A photoelectric sensor for projecting light on a detection region and receiving said light from said detection region, comprising:
 a main body portion including a light source for generating light, and a control portion for controlling said light source and performing signal processing; 
 a head portion provided separately from said main body portion and including a light-projecting portion for projecting light, and a light-receiving element for receiving said light; 
 an optical fiber cable through which light generated by said light source of said main body portion is led to said light-projecting portion of said head portion; and 
 an electric wire cable through which a signal output from said light-receiving element of said head portion is transmitted to said control portion of said main body portion. 
 
     
     
       2. A photoelectric sensor according to  claim 1 , wherein said light source has light-projecting elements for generating light with different wavelengths. 
     
     
       3. A photoelectric sensor according to  claim 1 , wherein:
 a signal output from said control portion of said main body portion is transmitted to said head portion through said electric wire cable; and 
 said head portion further includes an indicator portion for indicating information based on said signal transmitted from said main body portion. 
 
     
     
       4. A photoelectric sensor according to  claim 1 , wherein:
 said main body portion further includes a main body casing in which said light source and said control portion are stored and which has outer surfaces; and 
 said optical fiber cable and said electric wire cable extend out from a first outer surface included in said outer surfaces of said main body casing. 
 
     
     
       5. A photoelectric sensor according to  claim 4 , wherein:
 said main body portion further includes a main body indicator portion for indicating information based on said signal processing executed by said control portion; and 
 said main body indicator portion is provided on a second outer surface different from said first outer surface of said main body casing. 
 
     
     
       6. A photoelectric sensor according to  claim 4 , wherein said main body portion further includes:
 a connection portion through which said electric wire cable and said control portion are connected to each other; and 
 a first fixing member for fixing said electric wire cable to said connection portion. 
 
     
     
       7. A photoelectric sensor according to  claim 6 , wherein said main body portion further includes a second fixing member for fixing said optical fiber cable to said main body casing. 
     
     
       8. A photoelectric sensor according to  claim 1 , wherein said head portion further includes:
 a first polarizing member for polarizing light projected by said light-projecting portion to allow only light polarized in a first direction to pass through said first polarizing member; and 
 a second polarizing member for polarizing said light received by said light-receiving element to allow only light polarized in a second direction different from said first direction to pass through said second polarizing member. 
 
     
     
       9. A photoelectric sensor according to  claim 1 , wherein:
 said head portion further includes a head portion casing in which said light-projecting portion and said light-receiving element are stored and which has outer surfaces; and 
 said optical fiber cable and said electric wire cable extend out from a first outer surface included in said outer surfaces of said head portion casing. 
 
     
     
       10. A photoelectric sensor according to  claim 9 , wherein:
 said head portion further includes a light-receiving portion by which light from said detection region is led to said light-receiving element; 
 said head portion casing has a second outer surface opposite to said first outer surface; and 
 said light-projecting portion and said light-receiving portion are provided on said second outer surface of said head portion casing. 
 
     
     
       11. A photoelectric sensor according to  claim 9 , wherein:
 said head portion further includes a light-receiving portion by which light from said detection region is led to said light-receiving element; 
 said head portion casing has a second outer surface opposite to said first outer surface and a third outer surface different from said first and second outer surfaces; and 
 said light-projecting portion and said light-receiving portion are provided on said third outer surface of said head portion casing. 
 
     
     
       12. A photoelectric sensor according to  claim 9 , wherein:
 said head portion further includes a light-receiving portion by which light from said detection region is led to said light-receiving element; 
 said head portion casing has second and third outer surfaces opposite to each other and a fourth outer surface different from said second and third outer surfaces; and 
 said light-projecting portion and said light-receiving portion are provided on said second outer surface of said head portion casing; and 
 said first outer surface is provided between said third and fourth outer surfaces so as to be inclined. 
 
     
     
       13. A photoelectric sensor according to  claim 9 , wherein:
 a signal output from said control portion of said main body portion is transmitted to said head portion through said electric wire cable; and 
 said head portion further includes an indicator portion for indicating information based on said signal transmitted from said main body portion. 
 
     
     
       14. A photoelectric sensor according to  claim 13 , wherein said indicator portion is provided on another outer surface than said first outer surface of said head portion casing.